Here's something to 'bee' happy about: The number of honeybee colonies in the United States is on the rise after a worrying decline—up from 2.8 million in April, 2016 to 2.89 million in April, 2017, according to a report from the U.S. Department of Agriculture.

Since 2006, honey bees have been disappearing from their hives and dying at unprecedented rates due to a condition known as Colony Collapse Disorder. Because bees are credited with pollinating more than $15 billion of U.S. crops each year, their resurgence is also a bonus for the economy.

The insect's colonies are getting a bit of comeback help from some unlikely places. Groups such as the Pollinator Partnership, which promotes the preservation and creation of pollinator-friendly gardens and landscapes.

A growing number of airports—which tend to have lots of unused land conducive to eco-friendly projects—are playing host to beehives. In 2013, the Port of Seattle teamed up with The Common Acre, a local non-profit, to place clusters of honey bee hives on unused, open land at three Seattle-Tacoma International Airport locations.

In the U.S., there are apiaries on at Chicago's O'Hare International Airport, St. Louis Lambert International Airport, Seattle-Tacoma International Airport, Austin-Bergstrom International Airport and Albuquerque International Sunport.

Source: Chicago Dept of Aviation

O'Hare International Airport works with Sweet Beginnings to maintain on-airport apiaries.

In Victoria, British Columbia, Harbour Air just put four hives with 10,000 bees on the one-acre grass roof of its floating airport terminal for seaplanes. A "bee cam" lets passengers waiting in the airport lounge below watch the bees at work. Come fall, the airline plans to offer its own "Harbour Honey" to passengers to use as sweetener in their complimentary beverages.

Besides making a contribution to the local ecosystem, bee colonies are "an important way to educate people of all ages on the importance of honeybees to our local environment," said Bill Fosdick president of the Capital Region Beekeepers Association, which is overseeing the introduction of the bee colony.

In late 2015, Minneapolis-St. Paul (MSP) International Airport partnered with the "Bee Squad" program at the University of Minnesota to set up an apiary on airport property. Now, 31 colonies are being tended to by U.S. military veterans.

Last year's crop of honey was sold to Chef Andrew Zimmern (of "Bizarre Foods" fame) and to General Mills, to benefit the program. "We also gave some to the Veteran participants," said Bee Squad Program director Becky Masterman, "This year's extraction will be larger and we hope to sell some of the honey in the airport and have some used in MSP restaurants."

Source: Harbour Air

Hives on the roof of a floating airport terminal for seaplanes.

Beehives were also installed at Montréal-Trudeau airport in 2015, which came after a similar project at Montréal-Mirabel in 2014. Each airport is now home to about 300,000 honey bees. Some of the honey produced is sold to employees to raise funds for a local non-profit that helps low-income families and individuals; the balance is donated to local food banks.

At O'Hare, where the bee program is in its seventh season, there are currently 30 to 40 hives (down from a high of 75), and about one million bees on duty.

Operated by Sweet Beginnings, which gives training and jobs to ex-convicts and others who may have significant barriers to finding jobs, the apiary produces about 35 pounds of honey per hive.

Under the 'beelove' brand, products made with the O'Hare honey—including lip balm, skincare creams, soaps and, of course jars of raw national honey—are sold in Hudson News stores at O'Hare and in the Farmers Market kiosk in Terminal 3. Some O'Hare restaurants, including Tortas Frontera by Rick Bayless, also use the O'Hare honey in meals.

Like the symbiotic relationship between bees and flowers, both the airport and the non-profit get something valuable from the deal.

Seattle's Common Acre is collecting scientific data from the hives "crucial to understanding and supporting pollinators," said group founder Bob Redmond, who is selling the honey to help offset costs. Among other benefits, the bees help the airport keep large birds away from airplanes, by supporting the growth of dense vegetation on a former golf course area.